Ancient Ice Production

February 18, 2026 by Al Williams 53 Comments

Today, we take ice for granted. But having ice produced in your home is a relatively modern luxury. As early as 1750 BC, ancient people would find ice on mountains or in cold areas and would harvest it. They’d store it, often underground, with as much insulation as they could produce given their level of technology.

A yakhchāls in Yazd province (by [Pastaitkaen] CC BY-SA 3.0).

By 500 BC, people around Egypt and what is now India would place water in porous clay pots on beds of straw when the night was cold and dry. Even if the temperature didn’t freeze, the combination of evaporation and radiative cooling could produce some ice. However, this was elevated to a high art form around 400 BC by the Persians, who clearly had a better understanding of physics and thermodynamics than you’d think.

The key to Persian icemaking was yakhchāls. Not all of them were the same, but they typically consisted of an underground pit with a conical chimney structure. In addition, they often had shade walls and ice pits as well as access to a water supply.

Solar Chimney

The conical shape optimizes the solar chimney effect, where the sun heats air, which then rises. The top was typically not open, although there is some thought that translucent marble may have plugged the top to admit light while blocking airflow. yakhchālThe solar chimney produces an updraft that tends to cool the interior. The underground portion of the yakhchāl has colder air, as any hot air rises above the surface.

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Real LED TVs Are Finally Becoming A Thing

February 16, 2026 by Zoe Skyforest 58 Comments

Once upon a time, the cathode ray tube was pretty much the only type of display you’d find in a consumer television. As the analog broadcast world shifted to digital, we saw the rise of plasma displays and LCDs, which offered greater resolution and much slimmer packaging. Then there was the so-called LED TV, confusingly named—for it was merely an LCD display with an LED backlight. The LEDs were merely lamps, with the liquid crystal doing all the work of displaying an image.

Today, however, we are seeing the rise of true LED displays. Sadly, decades of confusing marketing messages have polluted the terminology, making it a confusing space for the modern television enthusiast. Today, we’ll explore how these displays work and disambiguate what they’re being called in the marketplace.

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The Engineering Of The Falkirk Wheel

February 13, 2026 by Al Williams 36 Comments

We live in an age where engineering marvels are commonplace: airplanes crisscross the sky, skyscrapers grow like weeds, and spacecraft reach for the stars. But every so often, we see something unusual that makes us take a second look. The Falkirk Wheel is a great example, and, even better, it is functional art, as well.

The Wheel links two canals in Scotland. Before you click away, here’s the kicker: One canal is 35 meters higher than the other. Before 1933, the canals were connected with 11 locks. It took nearly a day to operate the locks to get a boat from one canal to the other. In the 1930s, there wasn’t enough traffic to maintain the locks, and they tore them out.

Fast Forward

In the 1990s, a team of architects led by [Tony Kettle] proposed building a wheel to transfer boats between the two canals. The original model was made from [Tony’s] daughter’s Lego bricks.

The idea is simple. Build a 35-meter wheel with two caissons, 180 degrees apart. Each caisson can hold 250,000 liters of water. To move a boat, you fill the caissons with 500 tonnes of water. Then you let a boat into one of them with its weight displacing an equal amount of water, so the caissons stay at the same weight.

Once you have a balanced system, you just spin the wheel to make a half turn. There are 10 motors that require 22.5 kilowatts, and each half-turn consumes about 1.5 kilowatt-hours.

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The Weird Propeller That Offers Improved Agility On The Water

February 6, 2026 by Zoe Skyforest 49 Comments

When it comes to seaborne propulsion, one simple layout has largely dominated over all others. You pair some kind of engine with some kind of basic propeller at the back of the ship, and then you throw on a rudder to handle the steering. This lets you push the ship forward, left, and right, and stopping is just a matter of turning the engine off and waiting… or reversing thrust if you’re really eager to slow down.

This basic system works for a grand majority of vessels out on the water. However, there is a more advanced design that offers not only forward propulsion, but also steering, all in the one package. It may look strange, but the Voith Schneider propeller offers some interesting benefits to watercraft looking for an edge in maneuverability.

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I, Integrated Circuit

February 4, 2026 by Jenny List 78 Comments

In 1958, the American free-market economist Leonard E Read published his famous essay I, Pencil, in which he made his point about the interconnected nature of free market economics by following everything, and we mean Everything, that went into the manufacture of the humble writing instrument.

I thought about the essay last week when I wrote a piece about a new Chinese microcontroller with an integrated driver for small motors, because a commenter asked me why I was featuring a non-American part. As a Brit I remarked that it would look a bit silly were I were to only feature parts made in dear old Blighty — yes, we do still make some semiconductors! — and it made more sense to feature cool parts wherever I found them. But it left me musing about the nature of semiconductors, and whether it’s possible for any of them to truly only come from one country. So here follows a much more functional I, Chip than Read’s original, trying to work out just where your integrated circuit really comes from. It almost certainly takes great liberties with the details of the processes involved, but the countries of manufacture and extraction are accurate. Continue reading “I, Integrated Circuit” →

Building Natural Seawalls To Fight Off The Rising Tide

January 30, 2026 by Zoe Skyforest 40 Comments

These days, the conversation around climate change so often focuses on matters of soaring temperatures and extreme weather events. While they no longer dominate the discourse, rising sea levels will nonetheless still be a major issue to face as global average temperatures continue to rise.

This poses unique challenges in coastal areas. Municipalities must figure out how to defend their shorelines, or decide which areas they’re willing to lose. The City of Palo Alto is facing just this challenge, and is building a natural kind of seawall to keep the rising tides at bay.

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Does Carbon Fiber PLA Make Sense?

January 26, 2026 by Maya Posch 33 Comments

Carbon fiber (CF) has attained somewhat of a near-mystical appeal in consumer marketing, with it being praised for being stronger than steel while simultaneously being extremely lightweight. This mostly refers to weaved fibers combined with resin into a composite material that is used for everything from car bodies to bike frames. This CF look is so sexy that the typical carbon-fiber composite weave pattern and coloring have been added to products as a purely cosmetic accent.

More recently, chopped carbon fiber (CCF) has been added to the thermoplastics we extrude from our 3D printers. Despite lacking clear evidence of this providing material improvements, the same kind of mysticism persists here as well. Even as evidence emerges of poor integration of these chopped fibers into the thermoplastic matrix, the marketing claims continue unabated.

As with most things, there’s a right way and a wrong way to do it. A recent paper by Sameh Dabees et al. in Composites for example covered the CF surface modifications required for thermoplastic integration with CF.

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